1. The Field of the Invention
The present invention relates generally to orthopedic medicine, and more precisely, to systems and methods for restricting relative motion between vertebrae.
2. The Relevant Technology
Many people experience back pain. Back pain is not only uncomfortable, but can be particularly debilitating. Many people who wish to participate in sports, manual labor, or even sedentary employment are unable to do so because of pains that arise from motion of or pressure on the spinal column. Such pains are often caused by traumatic, inflammatory, metabolic, synovial, neoplastic and degenerative disorders of the spine.
In order to alleviate such injuries and pains, spinal fusion techniques have been used for many years to essentially lock two vertebrae together. More recently, artificial discs have been used to replace natural intervertebral discs to correct disc pathologies, while still permitting the adjacent vertebrae to move with respect to each other. Various implants have also been proposed for the partial or complete replacement of vertebral facet joints to alleviate discomfort associated with diseased or atrophied articular processes, while still permitting intervertebral motion.
It has been discovered that excessive anterior/posterior motion between adjacent vertebrae can damage the associated intervertebral disc (i.e., “slip” the disc). Diseased or damaged spinal segments may be especially vulnerable to such damage to the intervertebral disc. Unfortunately, known spinal implants that permit some form of relative motion between the vertebrae generally do not sufficiently restrict the action of shear forces on the vertebrae.